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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/* @test
 * @bug 8352969
 * @summary Tests optional evacuation.
 * @requires vm.gc.G1
 * @requires vm.debug
 * @library /test/lib
 * @build jdk.test.whitebox.WhiteBox
 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
 * @run driver gc.g1.TestOptionalRegionGC
 */

package gc.g1;

import jdk.test.lib.Asserts;
import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.lib.process.ProcessTools;
import jdk.test.whitebox.WhiteBox;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.Random;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class TestOptionalRegionGC {

  private static OutputAnalyzer run() throws Exception {
    return ProcessTools.executeLimitedTestJava(
      "-XX:+WhiteBoxAPI",
      "-Xbootclasspath/a:.",
      "-Xmx300M",
      "-Xms300M",
      "-XX:G1HeapRegionSize=1M",
      "-XX:+UseG1GC",
      "-XX:MaxTenuringThreshold=1",
      "-Xlog:gc+ergo+cset=trace",
      "-XX:+G1ForceOptionalEvacuation",
      "-XX:+VerifyAfterGC",
      TestOptionalRegionGC.Action.class.getName());
  }

  public static void main(String args[]) throws Exception {
    OutputAnalyzer out = run();
    out.shouldHaveExitValue(0);
    Pattern pattern = Pattern.compile("Prepared (\\d+) regions out of (\\d+) for optional evacuation");
    Matcher matcher = pattern.matcher(out.getOutput());
    Asserts.assertTrue(matcher.find());
    String selectedNum = matcher.group(1);
    String totalNum = matcher.group(2);
    Asserts.assertTrue(Objects.equals(selectedNum, totalNum), "Error info: " + selectedNum + ", " + totalNum);
  }

  public static class Action {
    private static final WhiteBox wb = WhiteBox.getWhiteBox();
    private static final int MIN_OBJECT_SIZE = 64 * 1024;
    private static final int MAX_OBJECT_SIZE = 120 * 1024;
    private static final int NUM_OBJECTS = 1200;

    public static void main(String [] args) throws Exception {
      // Remove garbage from VM initialization.
      wb.fullGC();
      Random rand = new Random(42);
      List<byte[]> objectList = new ArrayList<>();
      for (int i = 0; i < NUM_OBJECTS; i++) {
        int objSize = MIN_OBJECT_SIZE + rand.nextInt(MAX_OBJECT_SIZE - MIN_OBJECT_SIZE);
        byte[] obj = new byte[objSize];
        objectList.add(obj);
      }
      // Young GC promotes some objects to the old generation.
      wb.youngGC();
      // Clear certain references for mixed GC.
      for (int i = 0; i < NUM_OBJECTS; i+=2) {
        objectList.set(i, null);
      }
      wb.g1RunConcurrentGC();
      // Perform the "Prepare Mixed" GC.
      wb.youngGC();
      // Perform the "Mixed" GC.
      wb.youngGC();
    }
  }
}